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The VM now aborts when a wrong self pointer is used with user variables to avoid random crashes

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Leonard2 2016-09-14 13:56:58 +02:00 • committed by Christoph Oelckers
commit b5b9baaa87
6 changed files with 37 additions and 3 deletions
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13
src/thingdef/thingdef_expression.cpp
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@ -3373,6 +3373,19 @@ FxExpression *FxClassMember::Resolve(FCompileContext &ctx)
ExpEmit FxClassMember::Emit(VMFunctionBuilder *build)
{
if (~membervar->Flags & VARF_Native)
{ // Check if this is a user-defined variable.
// As of right now, FxClassMember is only ever used with FxSelf.
// This very user variable was defined in stateowner so if
// self (a0) != stateowner (a1) then the offset is most likely
// going to end up being totally wrong even if the variable was
// redefined in self which means we have to abort to avoid reading
// or writing to a random address and possibly crash.
build->Emit(OP_EQA_R, 1, 0, 1);
build->Emit(OP_JMP, 1);
build->Emit(OP_THROW, 2, X_BAD_SELF);
}
ExpEmit obj = classx->Emit(build);
assert(obj.RegType == REGT_POINTER);